Aragonite

Aragonite is a carbonate mineral, one of the two common, naturally occurring polymorphs of calcium carbonate, CaCO₃. Carbonate minerals are those Minerals containing the Carbonate Ion: CO32- Polymorphism in Materials science is the ability of a solid material to exist in more than one form or Crystal structure Calcium carbonate is a Chemical compound with the Chemical formula Ca[[Carbon C]] O 3 Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the The other polymorph is the mineral calcite. A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific Calcite is a carbonate mineral and the most stable polymorph of Calcium carbonate ( Ca[[carbon C]] O 3 Aragonite's crystal lattice differs from that of calcite, resulting in a different crystal shape, an orthorhombic system with acicular crystals. In Mineralogy and Crystallography, a crystal structure is a unique arrangement of Atoms in a Crystal. In Crystallography, the orthorhombic Crystal system is one of the seven Lattice Point groups Orthorhombic lattices result from stretching Repeated twinning results in pseudo-hexagonal forms. Crystal twinning occurs when two separate crystals share some of the same Crystal lattice points in a symmetrical manner Aragonite may be columnar or fibrous, occasionally in branching stalactitic forms called flos-ferri ("flowers of iron") from their association with the ores at the Carthinian iron mines. A stalactite ( Greek stalaktites, (Σταλακτίτης from the word for "drip" and meaning "that which drips" is a type of Speleothem An ore is a volume of rock containing components or Minerals in a mode of occurrence that renders it valuable for mining The type location for aragonite is Molina de Aragón (Guadalajara, Spain), 25 km outside Aragon. In some natural sciences type locality (Latin locus typicus) is the typical or representative location and is typically the first example of a newly discovered or described Guadalajara is a province of central/north-central Spain, in the northern part of the autonomous community of Castile-La Mancha. Spain () or the Kingdom of Spain (Reino de España is a country located mostly in southwestern Europe on the Iberian Peninsula. Aragon ( Spanish: "Aragón") is an autonomous community of Spain. An aragonite cave, the Ochtinská Aragonite Cave, is situated in Slovakia. Ochtinská Aragonite Cave ( Slovak: Ochtinská aragonitová jaskyňa, Hungarian: Ochtinai-aragonitbarlang the Magyar wikipedia article Slovakia (long form Slovak Republic; Slovak:, long form, is a Landlocked country in Central Europe with a population of over five million In the USA, stalactitic aragonite is known from Carlsbad Caverns. A stalactite ( Greek stalaktites, (Σταλακτίτης from the word for "drip" and meaning "that which drips" is a type of Speleothem Carlsbad Caverns National Park is a United States National Park located in the Guadalupe Mountains in southeastern New Mexico. Massive deposits of oolitic aragonite are found on the seabed in the Bahamas. Oolite ( egg stone) is a Sedimentary rock formed from Ooids spherical grains composed of concentric layers The Bahamas, officially the Commonwealth of The Bahamas, is an independent sovereign English -speaking country consisting of two thousand Cays and

Aragonite crystals (~ 4 cm in size)

Aragonite forms naturally in almost all mollusk shells, and as the calcareous endoskeleton of warm- and cold-water corals (Scleractinia). Molluscs are animals belonging to the phylum Mollusca. There are around 250000 extant Species within the phylum with an estimated 70000 Corals are Marine organisms from the class Anthozoa and exist as small Sea anemone –like Polyps typically in colonies of many Scleractinia, also called Stony Corals, are exclusively marine animals they are very similar to Sea anemones but generate a hard skeleton Because the mineral deposition in mollusk shells is strongly biologically controlled, some crystal forms are distinctively different from those of inorganic aragonite. In some mollusks, the entire shell is aragonite; in others, aragonite forms only discrete parts of a bimineralic shell (aragonite plus calcite). Aragonite also forms in the ocean and in caves as inorganic precipitates called marine cements and speleothems, respectively. The nacreous layer of the aragonite fossil shells of some extinct ammonites forms an iridescent material called ammolite. FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system. Ammonites are an extinct group of marine animals of the subclass Ammonoidea in the class Cephalopoda phylum Iridescence is an Optical phenomenon in which Hue changes with the angle from which a surface is viewed Ammolite is a rare and valuable Opal -like organic Gemstone found primarily along the eastern slopes of the Rocky Mountains of the United States Ammolite is primarily aragonite with impurities that make it iridescent and valuable as a gemstone. Iridescence is an Optical phenomenon in which Hue changes with the angle from which a surface is viewed A gemstone or gem, also called a precious or semi-precious stone, is a piece of attractive Mineral, which &mdash when cut and polished &mdash

Aragonite is thermodynamically unstable at standard temperature and pressure, and tends to alter to calcite on scales of 10⁷ to 10⁸ years. In Physics, thermodynamics (from the Greek θερμη therme meaning " Heat " and δυναμις dynamis meaning " In Physical sciences standard conditions for temperature and pressure are Standard sets of conditions for experimental measurements to allow comparisons to be made Calcite is a carbonate mineral and the most stable polymorph of Calcium carbonate ( Ca[[carbon C]] O 3 The young age of the California blueschists has been famously demonstrated by the finding therein of aragonite not yet reverted to calcite. Blueschist (ˈbluːʃɪst is a rock that forms by the Metamorphism of Basalt and rocks with similar composition at high Pressures and low The mineral vaterite, also known as μ-CaCO₃, is another phase of calcium carbonate that is metastable at ambient conditions typical of Earth's surface, and decomposes even more readily than aragonite. Vaterite ( Ca[[carbon C]] O 3 is a mineral a polymorph of Calcium carbonate.

Crystal structure of aragonite. O is red, Ca blue and C black. Carbonate groups are black triangles.

See also

White needle shaped aragonite crystals, Aragon, Spain

• list of minerals
• Monohydrocalcite, CaCO₃·H₂O
• Ikaite, CaCO₃·6H₂O
• Nacre, otherwise known as "Mother-of-Pearl"
• Pearl
• Ocean acidification
• Ochtinská Aragonite Cave

References

• Webmineral data
• Mineral Data Publishing
• Mindat

External links

• The Ochtinska aragonite cave